In an elderly man with known diverticulosis presenting with mild intermittent left lower quadrant pain, no fever, normal white blood cell count, and no peritoneal signs, what is the most appropriate initial management?

Initial Management: CT Abdomen with IV Contrast

In this elderly man with known diverticulosis presenting with mild intermittent left lower quadrant pain, normal inflammatory markers, and no peritoneal signs, the most appropriate initial management is CT abdomen and pelvis with IV contrast (Option A) to confirm the diagnosis and exclude complications or alternative pathology before initiating any treatment. 1

Why Imaging Must Come First

The World Society of Emergency Surgery (WSES) explicitly recommends against empirical treatment without imaging in elderly patients, as it can miss high-mortality conditions and leads to unnecessary antimicrobial exposure. 1 The evidence is compelling:

• Clinical diagnosis alone has a positive predictive value of only 65% in elderly patients, whereas CT imaging increases this to approximately 95% 1
• CT identifies the correct diagnosis in 43% of elderly cases that were clinically unsuspected, preventing missed serious pathology such as perforation or malignancy 1
• CT is essential to rule out alternative diagnoses that mimic diverticulitis in the elderly, including colorectal cancer, ischemic colitis, inflammatory bowel disease, bowel obstruction, and perforated viscus 1

Why Other Options Are Inappropriate at This Stage

Option B (IV Antibiotics and Bowel Rest) - Premature Without Imaging

For uncomplicated diverticulitis (WSES stage 0) in immunocompetent elderly patients, the WSES and American College of Gastroenterology advise no routine antibiotics, reserving them only for those with systemic signs (fever, leukocytosis), age > 80 years, immunocompromise, or confirmed complicated disease. 1, 2

• This patient has no fever and normal WBCs, making him a poor candidate for antibiotics even if diverticulitis is confirmed 1
• Initiating antibiotics before CT confirmation is discouraged by WSES because it leads to unnecessary antimicrobial exposure without proven benefit 1
• The decision to use antibiotics should only be made after CT confirms the diagnosis and severity 3

Option C (Increase Fiber and Fluid Intake) - Addresses Wrong Condition

• This patient has symptomatic disease (pain), not asymptomatic diverticulosis 4
• Fiber and fluid intake is appropriate for preventing diverticulosis progression in asymptomatic patients, not for managing acute symptoms 5
• The presence of pain warrants investigation to determine if this represents acute diverticulitis, which requires different management than simple diverticulosis 2

Option D (Laparotomy) - Grossly Inappropriate

Laparotomy is indicated only for: (1) generalized peritonitis with organ dysfunction (WSES stage 3–4), (2) free intraperitoneal air accompanied by diffuse peritonitis, or (3) failure of medical management in complicated diverticulitis. 1, 3

• This patient has no signs of peritonitis, making surgery completely unwarranted 1
• Postoperative mortality for emergent colon resection is 10.6%, making it a high-risk intervention reserved only for life-threatening complications 2

Management Algorithm After CT Confirmation

Once CT is obtained, management follows the WSES classification 1:

WSES Stage 0 (Uncomplicated, localized inflammation):

• Observation, clear-liquid diet, analgesia
• No antibiotics in immunocompetent patients without systemic signs 1, 2

WSES Stage 1a (Pericolic air/fluid < 4 cm):

• Consider oral/IV antibiotics (amoxicillin/clavulanic acid or cefalexin with metronidazole) 1, 2

WSES Stage 2a (Abscess ≥ 4 cm):

• IV antibiotics (ceftriaxone plus metronidazole or piperacillin-tazobactam) plus percutaneous drainage 1, 2

WSES Stage 2b–4 (Free air, diffuse peritonitis):

• Immediate surgical consultation; likely operative management 1

Critical Red Flags Requiring Urgent Re-evaluation

Patients should seek urgent medical attention if temperature exceeds 38°C, or if peritoneal signs develop (guarding, rebound tenderness, rigidity). 3

If symptoms persist beyond 2–3 days despite conservative management, repeat CT abdomen/pelvis with IV contrast should be obtained to reassess for complications or alternative pathology. 3

Common Pitfalls to Avoid

• Do not assume diverticulitis based on known diverticulosis alone - only 1-4% of patients with diverticulosis develop acute diverticulitis 2
• Do not delay imaging for clinical observation in elderly patients, as diagnostic accuracy without imaging is poor 1, 6
• Do not initiate antibiotics empirically in patients without systemic signs, as this increases resistance without improving outcomes 1, 3